Fuel tanks may experience increased pressure during certain operating conditions. The increased pressure may be caused by an increase in the temperature in a sealed fuel tank. The duration that a fuel tank is sealed may be increased in hybrid vehicles using both an electric motor and an internal combustion engine for motive power when compared to vehicles relying solely on internal combustion engines for motive power. The increase may be due, in part, to the sporadic use of the internal combustion engine in the hybrid vehicle. Consequently, the pressure in a fuel tank of a hybrid vehicle may reach levels that are many times greater than those experienced in systems where the fuel tank is routinely purged to the engine whenever necessary. In some circumstances the pressure in a fuel tank of a hybrid vehicle may be 15-20 times greater than the maximum values experienced by a fuel tank in a vehicle relying solely on an internal combustion engine for motive power.
To withstand increased pressure within the fuel tank thicker fuel tanks have been used, such as heavier gauge metal fuel tanks. However, the inventors herein have recognized various shortcomings of the above approach. For example, fuel tanks having increased wall thickness may not only increase vehicle costs but also increase the weight and size of the fuel tank. Moreover, the shape of the fuel tank housing may be selected based on the strength of the design rather than on the compactness of the design, decreasing the compactness of the vehicle or the fuel tank's storage capacity and therefore the driving range of the vehicle.
As such, various example systems and approaches are described herein. In one example, a distensible fuel tank included in a vehicle is provided. The distensible fuel tank includes a housing enclosing a lattice structure substantially spanning a portion of an interior defined by the housing, the lattice structure including a plurality of intersecting wall members, at least two of the wall members having an unequal thickness.
In this way, the thickness of the wall members may be varied to achieve a desired fuel tank structural integrity and stress deformation for a wide range of fuel tanks having different geometries. Further in some examples, other aspects of fuel tank's geometry may be altered to achieve desired fuel tank characteristics. For example, a separation between a first pair of successive wall members may not equal to a separation between a second pair of successive wall members. In this way, the separation between the wall members may be altered based on the geometry of the fuel tank.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.